Summary:
* UCAs improve Caster but reduce clearance at the rear fender.
* You can reduce the amount of space lost by setting the alignment optimally
* Daily driveability is much better after adding UCAs.

Not optimal obviously, but I had clearance and no rubbing issues at the back and did not need to do a cab-mount chop.

My wife noticed right away that the truck felt "skittish" and didn't like driving it. After six months, including a long road-trip to Moab, I decided I was ready to get some caster back, so I purchased some Light-Racing Upper Control Arms from wheelers.

But, there was a problem. The instant I tried to back out of my parking place with a bit of turn, the wheels rubbed the back of the wheelwell. brubrubrubrubrubrub.

I talked to the shop and rang up PRS 2 TiFJ. He gave the following observations and instructions.

* If you increase caster AT THE TOP of the spindle, you decrease clearance, because that moves the spindle hub back.
* If you increase caster AT THE BOTTOM of the spindle, you increase clearance, because that moves the spindle hub forward.
* On the stock truck, caster and camber must be played off against each other, because the combination of eccentric cams on the lower-control-arm affects both caster and camber.
* But the adjustability on the Light-Racings means you can set Camber at the top of the spindle, in addition to setting caster there.
* Toe is adjusted by the tie-rod ends, and is a completely separate adjustment.

So, to maximize clearance:

1. First, Maximize caster using the eccentrics on the lower control arm. Do not worry about camber at this time.
2. Reset the caster cams on the UCAs to the minimum value to bring Caster to an acceptable value. I decided to trade off a little less caster for a little more clearance here, and moved the UCA cams to the "+1" position (One degree LESS than neutral, and two degrees less than I started)
3. Set the camber using the UCA adjustment slide.
4. Finish off toe normally.

So I met with the alignment technician this morning, and stood in the shop while he worked. Pretty much my only contribution to the effort was showing how to turn the caster-adjustment cams on the UCAs. To get maximum "2.5" caster on my truck, the UCAs would have to be set at the neutral "+2" position. I deliberately traded off to get a little more CLEARANCE at the expense of a little less caster and ended up with the following final alignment numbers:

After the alignment, there was 2.5" of space between the tire and the rear of the fender well. A little less than I originally had before I installed the UCAs, but I'm no longer rubbing in the parking lot.

I'm now on the fence about getting a cab-mount-chop, because I hate tire rub in all its forms, and I like having the option to run chains on all four wheels.

The bonus to having waited this long to install UCAs is that I'm now qualified to talk "before and after" about driving the truck with and without upper-control-arms.

1: As expected, the truck now tracks better. On my short drive to the shop with the 3.7 degrees of caster, the truck was *very* stable and I kinda liked that. But even at 1.7, it's much more directionally stable, self-corrects easily to the zero position after the tiny variances in the road, and takes a lighter hand on the wheel. Truck no longer feels skittish or twitchy. I'm pleased.

2: The factory UCA ball joint, rather than OME shock length, seems to have been the limiting factor in droop. When I jack up the front end I now raise the whole thing two full inches (at the fender) before the tires finally leave the ground.

The amount of droop IS telling as I go over our various highway bridge joints that are a regular feature of my commute. Before, with the lift and the factory UCAs, the front would drop and the truck would lurch forward, forcing the headrest into the back of my head on some of these joints. Now, I glide easily over these small drops. This is an unexpected bonus, and I'm *very* pleased.

bjmoose gives a hearty "ThumbsUp" to Light Racing upper control arms.

Much later EDIT: - you may find this pic helpful in aligning the SPC control arms:

EDIT:
It's gotten harder to find the SPC install sheet online. I think SPC has taken the link to it off their website, so you can't easily find it via google anymore.

Summary:
* UCAs improve Caster but reduce clearance at the rear fender.
* You can reduce the amount of space lost by setting the alignment optimally
* Daily driveability is much better after adding UCAs.

Not optimal obviously, but I had clearance and no rubbing issues at the back and did not need to do a cab-mount chop.

My wife noticed right away that the truck felt "skittish" and didn't like driving it. After six months, including a long road-trip to Moab, I decided I was ready to get some caster back, so I purchased some Light-Racing Upper Control Arms from wheelers.

But, there was a problem. The instant I tried to back out of my parking place with a bit of turn, the wheels rubbed the back of the wheelwell. brubrubrubrubrubrub.

I talked to the shop and rang up PRS 2 TiFJ. He gave the following observations and instructions.

* If you increase caster AT THE TOP of the spindle, you decrease clearance, because that moves the spindle hub back.
* If you increase caster AT THE BOTTOM of the spindle, you increase clearance, because that moves the spindle hub forward.
* On the stock truck, caster and camber must be played off against each other, because the combination of eccentric cams on the lower-control-arm affects both caster and camber.
* But the adjustability on the Light-Racings means you can set Camber at the top of the spindle, in addition to setting caster there.
* Toe is adjusted by the tie-rod ends, and is a completely separate adjustment.

So, to maximize clearance:

1. First, Maximize caster using the eccentrics on the lower control arm. Do not worry about camber at this time.
2. Reset the caster cams on the UCAs to the minimum value to bring Caster to an acceptable value. I decided to trade off a little less caster for a little more clearance here, and moved the UCA cams to the "+1" position (One degree LESS than neutral, and two degrees less than I started)
3. Set the camber using the UCA camber adjustment slide.
4. Finish off toe normally.

So I met with the alignment technician this morning, and stood in the shop while he worked. Pretty much my only contribution to the effort was showing how to turn the caster-adjustment cams on the UCAs. To get maximum "2.5" caster on my truck, the UCAs would have to be set at the neutral "+2" position. I deliberately traded off to get a little more CLEARANCE at the expense of a little less caster and ended up with the following final alignment numbers:

After the alignment, there was 2.5" of space between the tire and the rear of the fender well. A little less than I originally had before I installed the UCAs, but I'm no longer rubbing in the parking lot.

I'm now on the fence about getting a cab-mount-chop, because I hate tire rub in all its forms, and I like having the option to run chains on all four wheels.

The bonus to having waited this long to install UCAs is that I'm now qualified to talk "before and after" about driving the truck with and without upper-control-arms.

1: As expected, the truck now tracks better. On my short drive to the shop with the 3.7 degrees of caster, the truck was *very* stable and I kinda liked that. But even at 1.7, it's much more directionally stable, returns easily to the zero position after the tiny variances in the road, and takes a lighter hand on the wheel. Truck no longer feels skittish or twitchy. I'm pleased.

2: The factory UCA ball joint, rather than OME shock length, seems to have been the limiting factor in droop. When I jack up the front end I now raise the whole thing two full inches (at the fender) before the tires finally leave the ground.

The amount of droop IS telling as I go over our various highway bridge joints that are a regular feature of my commute. Before, with the lift and the factory UCAs, the front would drop and the truck would lurch forward, forcing the headrest into the back of my head on some of these joints. Now, I glide easily over these small drops. This is an unexpected bonus, and I'm *very* pleased.

bjmoose gives a hearty "ThumbsUp" to Light Racing upper control arms.

Click to expand...

Awesome dude... glad I was able to explain it in a way that made sense. Great write up. I highlited a couple typos for ya.

So, the only caveat to this is that as you dial in most your caster at the bottom you will end up with positive camber. You are able to compensate for this at the top with the light racing UCAs by pulling the top in. this moves the ball joint closer to the coil, so be aware that the LRs use a very large boot on the ball joint and you may experience contact between the boot and the coils, especially for people using larger 2.5 diameter shocks. So, I recommend you check at some point that at full droop you are not contacting the coil.

Went wheelin last night, fucked up my door... and knocked my LR UCA out of adjustment in camber (along with my alignment). Went from all of the way out to almost all of the way in. I torqued them to spec with a torque wrench, this time I torqued them much more. Also noticed the boots had fallen down and they were pretty dry and had lot's of dirt inside. I will be needing to lube them.

Not a big deal but... shows you can knock the LRs out of adjustment and keep an eye on the ball joints to see if they have ample grease.

ball joints and bushings wore out on both sides in under a year. SPC replaced them at no cost to me (not even shipping). I had to install them myself but I had it down the second time, took no time at all. New design looks much better FWIW. I'd buy them again.

Very good info here as usual. I have been planning my lift for about a year now and have found your posts very very useful. Thanks for taking the time and effort to post all of this great info. Almost had the lift last year but found out at tax time instead of getting money back as we do each year we owed over 8 large. Purchased the LR UCAs for cyber Monday and finally saved enough for the OME lift. Now to find a good shop at a decent price for the install, can't wait!! Thanks again.

what are the correct numbers soposed to be on a taco that is lifted 3''

Click to expand...

I have read that ideal is 0 degrees for camber. 0 or +.01 or +.02 degrees of toe. And more than 2 degrees of caster.

This is achievable on an all stock Tacoma with no lift. However, when you lift the truck, especially when you max it out to 3" of lift, it becomes impossible to adjust the caster high enough. One degree of caster might be attainable but not much more.

Do you have 3" of lift? Have you added aftermarket upper control arms?

I have read that ideal is 0 degrees for camber. 0 or +.01 or +.02 degrees of toe. And more than 2 degrees of caster.

This is achievable on an all stock Tacoma with no lift. However, when you lift the truck, especially when you max it out to 3" of lift, it becomes impossible to adjust the caster high enough. One degree of caster might be attainable but not much more.

Do you have 3" of lift? Have you added aftermarket upper control arms?

Click to expand...

Toe ~0* (out of spec toe can cause adverse handling and the scuffing and dragging or pushing of tires across pavement, you want both your tires straight ahead and parallel to each other, lifting should not affect this)

Camber would depend on your application mostly you want 0* this puts the tire as about as close to 90* to the road as possible. Some go fast guys may want a little negative camber to help with cornering. /-----\

Caster you want as much as you can squeeze out of these guys IMO, I think about 3* is a good number. This will dictate how your truck handles, too little caster and your truck will feel like it's 'floating' and following grooves and ruts in the road, wandering etc... too much and it makes it more difficult to turn. I'm of the opinion that you'll never seen enough caster on these trucks to make it an issue.

Since caster and camber are both adjusted via the cams at the LCA and the UCA is fixed there is only so much adjustment possible. When you lift you basically get positive camber and so to bring that camber down you have to take a hit in your caster angles.

If you were looking at your truck after you lifted it you might notice the positive camber which would look like this from the front. \-----/

This gives you decreased contact with the road way and wears your tires on the outside unevenly which severely shortens their life.

So like I said to bring them back down to as close to 0* as possible |-----| you have to take a hit at caster making it lower, this causes your truck to wander and track poorly. I could only get 1* with stock UCAs and 884 coils. With about .5 camber.

So when you add LR UCAs you get much greater adjustability because now we can add or remove both caster and camber at the UCA and LCA.

This means we can get ideal alignment numbers if we know how to set up the UCAs.

The stock specs are as follows: (note that they may not be the most ideal)